Monthly Archives: June 2015

After building a few frames I felt the need to build myself a tube butt gauge. When building a frame the tubes have a “short butt” and a “long butt” (pause for jokes…… 🙂 ). A butt is when the tubes are thicker at the ends (near the joints) for strength. The manufacturer of the tube often paints one end to identify the short or long side. Columbus , for example paints the short butt.

Why? The short butt is the starting point. Make your first miter there then, when you trim the tube to length the long butt will leave you enough thicker wall to braze (or weld) on.

Just to make sure I have my butts in order I figured I’d make this simple gauge.

The idea is to have two posts run parallel and about an inch apart, with a dial indicator perpendicular to measure the difference.

This will be the base that holds the two posts apart and parallel.

While I braze bike frames I can still tig weld…. sorta. Ha!

The top hole holds the dial indicator and the bottom hole is tapped for a 10-32 screw. The screw supports the ID of the tube.

The final product.

You might not be able to read what’s written on the tubes so I’ll type it out. Where the indicator is in the above pic the tube is .038″ thick. Then the wall thickness tapers to .024″ thick.

Like this.^

Henry James / True Temper shows this very well. The butt on the left is the short butt.

While on my lunch breaks and after work I have been building my own frame jig. Jigs generally sell for $2500 to $5 grand. Since I have access to CNC machines I could make a jig for penny’s on the dollar of a professional jig. Will there be better ways to go about building a jig? I’m sure there are but, I can happily say that I have designed (with a little internets help) and built my own from scratch. Will it be as easy to set-up or make slight tweaks, doubt it. However saving upwards of $4500 can allow me to be a pinch inefficient in the beginning.

My design is obviously based off of the Arctos Jig.

I started with a really rough sketch and figured out the main pieces of 80/20 extrusion needed (like Arctos). EBay is an amazing source for 80/20. They have their own direct store on eBay. 80/20inc. is the username.

Then rounded up some other stock supplies from McMaster to make the HT and ST holders.

These smiley face brackets allow for angular and position in X and Y.
X being the length of the frame while Y is the height.

So’ together is looks like this. The main beam is 45/15 (meaning 4.5″ x 1.5″) and the HT and ST uprights are 15/15. The main beam is 60″ long and may or may not get cut down in the end. A little extra length never hurt anyone right?

Next I found a nice picture of the BB fixture. I made it a bit more compatible with other forms of BB’s. In case I make a BMX frame one day.

In an effort to make all my frames ride straight I needed a way to check the alignment. Not having the funds for an alignment table I decided to improvise. Making a bottom bracket post and using a milling machine table I will be able to do so.

After turning I get to use the tap handle my Grandpa gave me. I love using stuff he used when he was my age. 🙂

Then I took it from the CNC lathe to a good ole manual Bridgeport mill to drill mounting holes.

You get the picture using a BB shell.

It’s first use will be on Adam from Rotten Gear’s frame.

UPDATE:
I used the BB post to align Adam’s BB and ST. Turns out the frame nails held very well as the ST was only .005″ out along the whole tube! Not bad for a noob!
Damn I’ve gotta get myself a CNC machine for my shop! Ha!

As I learn about frame construction I like trying different things. With Adams frame I wanted to try a couple things. One was using nails to keep the tubes and lugs in place while brazing.

So per recommendation from Greg from Magic Cycle Werks I went to good old Home Depot and picked up a box of unplated, steel finishing nails. They are about .070″ in diameter so it’s not like I’m drilling quarter inch holes in my lugs or anything.

The other thing I wanted to try was better flux. I love McMaster Carr just like anything else but the flux they sell gets no such love from me. I ordered some System 48 flux from Cycle Design USA. Since Wade is a nice guy he sent me an oz. of System 48 Silver to try also. I also got some Fillet Pro to try for later. 😉

Ok, so, nail it all together, check it…

Close enough.

Flux, heat, silver and bam!

I really liked how the System 48 flux didn’t flake off and stayed active the whole time! The silver flowed threw with ease and filled slight gaps better than Harris Safety Sil 56.

Now to soak, trim off the nails and done!

This is also the first time I build a frame from start to finish entirely in my own shop! So much firsts!

Dropouts! I think dropouts are one of the coolest parts of a frame. They can show how serious or how artsy a frame is. Classic Campy look, breezer style, low disc mount…. can change the look and feel of a frame all by themselves.

I really like these. I used them on my SS frame and they look clean and are strong as hell looking! Naturally since Adam is a big dude, strength is a concern. These Long Shin track dropouts fit the bill to a tee.

They are plug in style so brazing is simple!

If you don’t like the clean-cut cycling gear out there check out Rotten Gear! My buddy Adam has some obvious metal/horror/hardcore influences. If you’re into the same thing he is and you don’t see what you like there, give him time. Kits will be coming! Like his page! This guys doodles are amazing! Can’t wait to see when he gets serious!

Thanks for checking this post out. There’s plenty more to be done on this frame so expect to see another post soon!